1. Field of the Invention
The present invention relates to a video image processing apparatus that transfers hierarchically-encoded video data in which a plurality of video data with different fields of view has been subjected to hierarchical coding, to an external reproducing apparatus, and a control method therefor.
2. Description of the Related Art
In recent years, a function of transferring video data stored in a recording device such as a hard disk recorder to a reproducing apparatus such as a portable terminal has come into wide use. In such a video data transferring function, a technique for transferring video data matched to a capability of the reproducing apparatus at a transfer destination is being studied. Japanese Patent Application Laid-Open No. 2001-136371 discusses a technique for converting video data into resolutions suitable for the reproducing apparatus at the transfer destination according to the acquired information by acquiring information of display resolution from a reproducing apparatus at a transfer destination.
Japanese Patent Application Laid-Open No. 2006-067576 discusses a technique for transferring video data as it is, if the video data is suitable for reproduction in the reproducing apparatus at the transfer destination, and for transferring by reencoding the video data, if not suitable.
Transferring the video data hierarchically-encoded by the hierarchical coding technology specified in H.264/Scalable Video Coding (SVC) standard or the like while using such video data transferring function is also conceivable.
Video data encoded in accordance with the H.264/SVC standard contains a plurality of resolution layers (video data with a plurality of resolutions). For this reason, in a case where the video data encoded in accordance with the H.264/SVC standard is transferred to external reproducing apparatuses, the video data with resolutions matched to the reproducing apparatus at the transfer destination can be transferred, by deleting unnecessary resolution layers in the reproducing apparatus at the transfer destination. However, in the H.264/SVC standard, since different fields of view, that are ranges of video images to be displayed, can be set according to a resolution layer, there is a case where the video data is hierarchically-encoded by a plurality of layers with resolutions and fields of view which are both different from one another. In this case, if the layer is deleted just because it is an unnecessary resolution layer, video image with a field of view of the deleted layer cannot be reproduced.
In other words, if the video image is transferred by deleting layers using information of resolutions, a problem may appear that types of fields of view of the video data which can be reproduced by the reproducing apparatus at the transfer destination will be restricted, depending on the deleted layers.
On the other hand, as a solution for the above-described problem, if the hierarchically-encoded video data is directly transferred as it is to the external reproducing apparatuses, without deleting the layers, even the video data with a resolution exceeding display capability of the reproducing apparatus may be transferred in some cases, depending on a configuration of the layers. Accordingly, it is inefficient to transfer the hierarchically-encoded video data as it is, and it causes a problem in some cases that it increases transfer time to the reproducing apparatus, or presses storage capacity of the reproducing apparatus. In the techniques described in the above-described patent document, a method for solving these issues is not discussed.